This invention relates generally to restriction indicators, and more particularly to restriction indicators for use with combustion engine intake air cleaners.
Restriction indicators are commonly used to indicate when it is recommended to service the air cleaner system of an internal combustion engine. Engine air cleaner systems usually use barrier filtration media that requires periodic servicing to ensue that adequate air flow is provided to the engine. Restriction indicators typically are connected to the air outlet of the air cleaner system upstream of the intake of the engine. Many mechanical restriction indicators employ a bellows-type diaphragm vented to the atmosphere, which is resisted from expanding by a compression spring. As the air cleaner system becomes more contaminated, the differential pressure between the xe2x80x9catmosphericxe2x80x9d /high pressure side and the xe2x80x9cnegativexe2x80x9d /low pressure side of the restriction indicator increases, thereby causing the diaphragm to expand. When the differential pressure has reached a certain level, the diaphragm typically becomes locked in an expanded position, and a constant warning signal is provided to the user that the air cleaner system is recommended to be serviced. An example of such prior art restriction indicators is shown in U.S. Pat. No. 3,443,365.
A problem associated with restriction indicators is providing a locking mechanism which will consistently lock and release after repeated use. In many designs, the locking mechanism includes a resettable plunger which engages a latch to lock the diaphragm in an expanded warning position. An example of this is shown by the ""365 patent, in which the plunger is bent to engage the latch off-center. Another example is shown by U.S. Pat No. 4,445,456 which discloses a restriction indicator having a ratchet that swings through an arc and interlocks with a floating indicator. An inherent disadvantage of this indicator is that side loads from the ratchet can cause canting, misalignment, friction and binding of the floating indicator.
According to the present invention, a restriction indicator for an air cleaner system is provided.
One aspect of the present invention relates to a restriction indicator for an air cleaner system of an internal combustion engine. The restriction indicator includes a housing divided into first and second chambers by a diaphragm. A signal member is connected to the diaphragm. The signal member is moveable along an axis between a reset position and a first indicator position, and defines an axial opening within which a first retaining shoulder is located. A guide member is provided for guiding the signal member as the signal member is moved between the reset position and the first axial position. A retaining member is provided for retaining the signal member in the first indicator position. The retaining member extends within the axial opening of the signal member and includes at least two fingers that project radially outward from the axis. The fingers are configured to engage the first retaining shoulder to retain the signal member in the first indicator position. The restriction indicator further includes a reset button for deflecting the fingers radially inward to disengage the fingers from the first retaining shoulder thereby allowing the signal member to be returned to the reset position. The reset button includes a portion that extends within the axial opening of the signal member between the retaining member and the signal member.
These and other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto. However, for a better understanding of the invention and its advantages, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter in which there are illustrated and described preferred embodiments of the invention.